Dispenser for applying liquid, in particular for applying a pharmaceutical liquid, and set comprising such a dispenser

ABSTRACT

A dispenser for applying liquid, having a housing with an applicator opening and a liquid reservoir. The dispenser has a ventilation duct by which an ambient atmosphere is connected to the liquid reservoir so that, after the application of liquid, an inflow of air from the atmosphere is permitted into the liquid reservoir. The dispenser is provided with a detection installation which for detecting an application procedure detects air flowing in through the ventilation duct. The dispenser has a protective cap covering the applicator opening on the housing. The dispenser in the ventilation duct has a switch valve operable by activating a push-button on the external side of the housing. The protective cap acts on the push-button when placed on the housing or when the protective cap is being placed thereon to open the switch valve.

FIELD OF APPLICATION AND PRIOR ART

The invention relates to a dispenser for applying liquid, in particularfor applying a pharmaceutical liquid, and to a set comprising such adispenser.

A dispenser of the generic type, like a dispenser according to theinvention, possesses a housing having an applicator opening throughwhich liquid from a liquid reservoir of the dispenser can be delivered.This can take place, for example, in that the liquid reservoir isconfigured as a squeeze bottle and is manually compressed for thepurpose of the application.

As a result of the application, a negative pressure by virtue of thedispensed liquid volume is generated in the liquid reservoir indispensers of the generic type or according to the invention. In orderfor this liquid volume to be compensated, the dispenser has aventilation duct by way of which air can be inducted into the liquidreservoir. For the purpose of the avoidance of contamination, theventilation duct can be provided with a filter assembly.

Depending on the design embodiment of such a dispenser, the latter canbe configured for applying a dose of liquid as defined by theconstruction of said dispenser per activation, or for applying aquantity of liquid which can be freely determined by the type ofactivation by the user.

In a dispenser of the generic type or according to the invention it canbe desirable for the applied quantity of liquid, or the number ofapplied doses of liquid, to be detected, in particular by electronicmeasuring means. This can be desirable both in the typical operation ofsuch a dispenser at the end-user or else in a trial phase by specialproduct testers. The purpose may be, for example, to estimate theresidual quantity of liquid in the liquid reservoir, or to enable theuser to be reminded when an envisaged application has not beenperformed.

Diverse measuring systems for liquid dispensers in which the activationper se is detected and processed in particular in the form of countingare already known from the prior art. However, in such systems it is notguaranteed in every case that a correct application has actually beenperformed, for example not when the dispenser when activated was notaligned according to the intended use.

It has likewise already been considered to detect the flow of liquid perse, thus to add a sensor to a suitable measuring installation in anapplicator duct between the liquid reservoir and the applicator opening.This however is often difficult to implement in terms of constructionand leads to a substantial change in the construction of a dispenser.Depending on the materials used in a corresponding sensor system, thecontact between the liquid and this sensor system is alsodisadvantageous in terms of the sensor system and/or the liquid.

Object and Achievement

it is an object of the invention to provide a dispenser which in anadvantageous manner permits the detection of the liquid application andherein avoids or minimizes the above-mentioned issues of the prior art.

Proposed according to the invention to this end is a dispenser forapplying liquid, in particular for applying a pharmaceutical liquid.

In accordance with dispensers of the generic type, such dispensersaccording to the invention have a housing having an applicator openingfor applying liquid, and a liquid reservoir for storing the liquid priorto the application. The dispensers according to the liquid are portabledispensers for the end-user and in particular for patients, hereundercollectively referred to as users. The maximum volume of the liquidreservoir therefore is usually between 5 ml and 500 ml, in particularbetween 5 ml and 50 ml.

Upon activation by the user, the liquid in the liquid reservoir isconveyed through an applicator duct to the applicator opening. An outletvalve which only opens upon reaching a defined threshold pressure ispreferably disposed upstream of the applicator opening. The form ofapplication can in particular be that of a liquid flow, an atomizedspray jet mixed with air, or the form of individual drops. In the caseof a drop dispenser, the applicator opening is surrounded by adrop-forming surface to which the liquid to be delivered adheres untilthe quantity of liquid is sufficiently large to be released in the formof drops from the drop-forming surface. The drop-forming surfaceexternally is preferably delimited by a tear-off edge, so as toguarantee a particularly uniform size of drop.

A manually activatable pump installation, having a pump chamber and pumpvalves on the input side and the output side can in particular beprovided for conveying the liquid from the liquid reservoir to theapplicator opening. A particularly substantial alternative thereto isthe design of the dispenser as a squeeze-bottle dispenser. In this case,the liquid reservoir, or a surrounding activation member, is elasticallycompressible so that a positive pressure which causes conveying in thedirection of the applicator opening is generated in the liquid.

In a dispenser according to the invention it is provided that, uponcompleting an application and when resetting the liquid reservoir or thesurrounding activation member, air from the environment is inducted intothe liquid reservoir so as to compensate for the previously appliedliquid volume and to adapt the pressure in the liquid reservoir to theambient pressure again.

For this purpose, a dispenser according to the invention possesses aventilation duct by means of which an ambient atmosphere is connected tothe liquid reservoir so as to, after the application of liquid, permitan inflow of air from the atmosphere.

According to the main aspect of the invention, the dispenser furthermorepossesses a detection installation for detecting an applicationprocedure, wherein the detection installation is configured fordetecting the air flowing in through the ventilation duct.

According to the main aspect of the invention it is accordingly proposedthat neither the activation of the dispenser nor a direct detection ofthe applied liquid volume is utilized for detecting the application, butinstead the ventilation procedure which follows the application and inthe context of which air, in particular from an ambient atmosphere,flows into the liquid reservoir or a surrounding activation member.

It has been demonstrated that an application can be reliably identifiedherewith, wherein only the performance of the application per se or elsethe applied liquid is able to be indirectly detected, depending on thedesign embodiment. Contact between the liquid and a corresponding sensorsystem can be avoided here. Any activation of the dispenser which hasnot led to an application of liquid, and therefore also does not lead toan inflow of air, correctly does not result in a detection.

A detection installation in the most general form is a mechanism whichvaries the state thereof in a reproducible manner when an event,presently the induction of air, takes place. While purely mechanicalconstruction modes appear to be conceivable here, an electronicdetection installation is preferably provided in a dispenser accordingto the invention, thus a detection installation having a sensor and amemory, the latter as a consequence of the application proceduredetected indirectly by sensors changing the state of its memory. Asensor according to the invention is disposed in or on the periphery ofthe ventilation duct and directly detects the air flow directed therebyinto the liquid reservoir, and thus indirectly the previously performedapplication of liquid.

Various sensors can be considered for detecting the inflow of air.

The detection installation can thus have a sensor assembly for detectingthe air flowing in through the ventilation duct, said sensor assemblybeing configured for detecting a differential pressure between twolocationally spaced apart reference points of the ventilation duct. Thiscan take place in particular in that a bypass piece which is closed offby means of a deflectable surface portion is provided in the ventilationduct or a particular part thereof (measuring duct). This membrane isdeflected as a function of the differential pressure, which can beelectronically detected. A deflectable surface portion can also directlyform a wall part of the ventilation duct, and be deflected as a functionof the pressure prevailing therein. A further design which can beutilized in the context of the invention provides that the sensorassembly comprises at least two temperature sensors and at least oneheating element which are disposed in the ventilation duct, wherein thetwo temperature sensors are provided upstream and downstream of theheating element. The detection installation can draw a conclusionpertaining to the quantity of inflowing air from the temperaturedifference of the temperature sensors and the output of the heatingelement.

A potential design of the dispenser according to the invention and thedetection installation thereof provides that the detection installationdetermines the quantity of liquid previously applied indirectly by wayof the air flowing in through the ventilation duct, and displays thedetermined applied quantity of liquid, or the quantity of liquidremaining in the liquid reservoir calculated from the former, on adisplay installation. The display installation can be designed as adisplay, for example an LC display. Depending on the specificapplication, a simple LED may be sufficient, in particular when thedisplay installation is intended to display only whether the determinedapplied quantity of liquid corresponds to a predetermined quantity ofliquid, or exceeds the latter or is deficient in terms of the latter.

Another design provides that the detection installation is configuredfor identifying application procedures as such indirectly by way of theair flowing in through the ventilation duct, wherein it is not requiredto this end here that the applied quantity of liquid is mandatorily alsodetected in terms of the quantity of the latter. Such a design of adetection installation, and the sensor system of the latter, are easierto design in technical terms, but are sufficient depending on the fieldof application.

In a dispenser which for reasons of construction always dispenses dosesof liquid of identical size, the information that an application hasbeen performed can thus be sufficient for counting. Such a detectioninstallation in conjunction with an integrated clock can also beconfigured for comparing planned utilization times and performedapplication procedures and, in the event of outstanding applicationprocedures at planned utilization times, to emit a preferably acousticwarning signal by way of a signaling installation.

The detection installation described can be integrated directly in anapplicator head of a dispenser according to the invention. In the caseof single-use dispensers this is however in most instances ratheravoided for reasons of ecology and economy. Instead, the disposal in anexternal module and the disposal in the protective cap, as will yet beexplained hereunder, are preferable.

First for the disposal of the detection installation in an externaldetection module, wherein this detection module is comprised by theinvention both in combination with a dispenser (set) to which saiddetection module is attached, as well as a standalone item.

Such an external detection module can be attached to the housing of thedispenser, preferably in a tool-free manner, and be released from saidhousing preferably in a tool-free manner. Depending on the specificapplication, the potential of attaching said detection module only bymeans of a tool may however be sufficient. Even when fixedly attached tothe dispenser, the module does however not represent an integral part ofsaid dispenser. This means that the module is removable withoutpreventing the functional capability of the dispenser for applyingliquid.

The external detection module can be attached to the housing of thedispenser in such a manner that said external detection module sitsfirmly thereon and can no longer be inadvertently released. Simplehandling is advantageous if the external module is to be handled byend-users. In this case, the external module is preferably pushed ontothe housing in a force-fitting manner, or secured in a form-fittingmanner, in particular by means of the thread, against being pulled off.

The detection module is configured for coupling externally to thatlocation of the housing of the dispenser where an induction opening intothe dispenser-proximal part of the ventilation duct is provided.

The detection module per se has a measuring duct, and at the end thereofa coupling port, wherein the coupling port is positioned in such amanner that the measuring duct, upon attaching the detection module, iscoupled so as to communicate with the induction opening on the housingof the ventilation duct of the dispenser. An external side of thehousing and an internal side of the detection module conjointlypreferably delimit an encircling duct to which the induction opening aswell as the coupling port are connected in a communicating manner. Themeasuring duct, upon coupling, forms part of the ventilation duct.

The detection module preferably but not mandatorily has an annularmodule housing which surrounds a central recess such that said modulehousing can be pushed onto the dispenser housing so as to surround thelatter.

The design of the detection installation as part of an externaldetection module in construction terms is in most instances advantageousin comparison to a solution in which the housing is integrated in thedispenser. This permits the production and/or the use of the dispenserin a design with the detection installation and a design without thedetection installation, without the dispenser components which arerequired for the application of the liquid, and in particular thehousing, of said designs having to be specially designed. Moreover, evendispensers which already commercially available nowadays can beretrofitted with a detection module as long as the induction opening isprovided at a location of the housing that is suitable for coupling adetection module.

Furthermore, an external detection module can be removed in a simple,and particularly preferably tool-free, manner from an emptied single-usedispenser, and be placed onto a new dispenser, which is advantageous interms of economy and ecology. A particular design embodiment of thedetection module can therefore be configured having a sensor system inorder to register such a dispenser replacement and utilize thisinformation for a reset procedure. For example, a counter can be resetto zero.

As has already been mentioned above, the design of a protective caphaving an integrated detection installation is also advantageous. Beforethis will be discussed in detail, the design of an inventive dispenseraccording to a second aspect of the invention will first be explained,wherein this design serves in particular as the foundation for the useof a protective cap having a detection installation.

In this second design, a dispenser of the generic type is equipped witha protective cap for covering the applicator opening in the state placedthereon. The protective cap is removed by the user of the dispenserbefore the dispenser is used, and subsequently replaced. Said protectivecap can in particular be a plug-fit cap or a screw cap.

The dispenser according to this second aspect of the invention in theventilation duct has a switch valve which can be opened by activating apush-button provided on the external side of the housing. Theventilation duct is thus closed when the switch valve is not activated.An induction of air is suppressed. The switch valve is preferablyprovided in the region of an external surface of the housing of thedispenser such that said switch valve suppresses the ingress of air intothe ventilation duct.

In order for the mentioned push-button to be activated it is providedthat the housing and the protective cap are mutually adapted in such amanner that the protective cap acts on the push-button in the stateplaced on the housing or when the protective cap is being placed on thelatter, thus opening the switch valve. This means that the procedure ofplacing the protective cap, at least in the interim, has the effect ofopening the switch valve, thus permitting the inflow of air.

In such a design of the dispenser it is thus not provided that solelythe application of liquid, and the negative pressure arising as a resultin the liquid reservoir, enables the induction of air. Instead, thenegative pressure is initially maintained, and is optionally evenreinforced by activating the dispenser multiple times, and accordinglyby a multiple application of liquid. The ventilation can take place onlyonce the protective cap is placed onto the housing again.

This has a plurality of advantages. Independently of the presence of adetection installation, a negative pressure which tends to be moreintense, and a greater air flow of the inflowing air caused as a result,can be advantageous, for example in order to release remnants of liquidfrom a liquid filter at the end of the ventilation duct.

A design embodiment of this type of a dispenser is however particularlyadvantageous in particular when said dispenser has a detectioninstallation of the type described above. Such a detection installationin terms of the sensor system thereof is easier to design in technicalterms when a greater air flow is detected, such as can be achieved byblocking the ventilation duct by means of the switch valve in theinterim.

It is particularly advantageous for the detection installation to beintegrated in the protective cap. This results in the advantages whichhave already been discussed above in the context of the externaldetection module, in particular the re-usability and the possibility ofbeing able to offer dispensers with and without a detection installationwhile having a high degree of identical construction.

In the case of the detection installation being integrated in theprotective cap, said detection installation is preferably designed ashas likewise been described in the context of the external detectionmodule, thus having a measuring duct in or on which the sensor system isprovided, and which by placing the protective cap thereon becomes partof the ventilation duct. The activation surface for activating thepush-button of the switch valve which is provided on the protective capis preferably disposed in such a manner that the measuring duct of theprotective cap and the ventilation duct in the housing are connected ina communicating manner and so as to be tight in relation to anenvironment in the transition region, such that the cap-proximaldetection installation can directly detect the air flow as soon as theswitch valve is opened by means of the protective cap when the latter isput in place.

The detection of the inflowing air in the context of placing theprotective cap can also be advantageous because said detection requiresonly a brief phase during which the electronics of the detectioninstallation are activated. It is therefore particularly advantageousfor the detection installation to possess a switch which is activatableby placing the protective cap on the housing.

The triggering of this switch, which in a detection installation withinthe housing of the dispenser may also form a common functional unit withthe switch valve, activates the detection installation. The detectioninstallation can be deactivated again as soon as the air flow, which issubsequently detected by sensors, is closed off and has been evaluated.Only a small amount of electric power is thus consumed. A battery aspart of the detection installation can therefore offer power for theoperation of the detection installation over a long time, optionally aplurality of years.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and aspects of the invention are derived from theclaims and from the following description of preferred exemplaryembodiments of the invention which are explained hereunder by means ofthe figures in which.

FIGS. 1 and 2A and 2B show a dispenser known per se as a starting pointfor the designs according to the invention which will be describedhereunder and the fundamental functioning mode of this dispenser;

FIG. 3 shows a first exemplary embodiment of the invention, having adetection installation integrated in the dispenser;

FIGS. 4A and 4B show a second exemplary embodiment of the invention,having an external detection module; and

FIGS. 5A and 5B show a third exemplary embodiment of the invention,having a detection module which is integrated in a protective cap.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

FIGS. 1A and 2A and 2B first show a liquid dispenser according to thegeneric type, which in the further course will be refined bymodification or addition so as to form a liquid dispenser according tothe invention.

The liquid dispenser 10 possesses an applicator device 12 whichrepresents the primary component of the liquid dispenser 10 and in turnpossesses a housing 20 which at the distal end is penetrated by anapplicator opening 22. In order for this applicator opening 22 to beprotected, the dispenser 10 comprises a protective cap 14 which ispresently configured as a ventilated protective cap so as to in theplaced state allow remnants of liquid remaining on the applicatoropening 22 to escape rapidly through ventilation holes 16.

The applicator device 12 possesses a liquid reservoir 30, the walls ofthe latter representing a squeeze bottle, as is yet to be explainedhereunder. An applicator head, which apart from the applicator opening22 already mentioned provides an applicator duct 24 which connects theliquid reservoir 32 to the applicator opening 22 is placed on the liquidreservoir 30. An outlet valve 26 which at a sufficient liquid pressurein a valve chamber opens and thus permits the liquid to exit through theapplicator opening 22 is disposed upstream of the applicator opening 22.The dispenser 10 is presently configured as a drop dispenser and beyondthe applicator opening 22 possesses a drop-forming surface 23 whichexternally is delimited by a tear-off edge.

As has already been mentioned, the liquid reservoir 30 is a liquidreservoir 30 configured in the manner of a squeeze bottle. This meansthat the activation of the dispenser, in the manner highlighted by FIG.2A, takes place in that the bottle is compressed in the direction of thearrows 6. As a result, a positive pressure is created in the liquidreservoir 30, having the effect that liquid is conveyed along the exitpath 7 to the applicator opening 22 and the drop-forming surface 23 andat the latter is delivered in the shape of drops. In the absence of theimpingement of the squeeze bottle by force, the latter re-assumes theinitial shape thereof in the manner highlighted by the arrows 8 in FIG.2B, as a result of which a negative pressure arises in the liquidreservoir 30. This has the effect that air is inducted through aventilation duct 40, along the ventilation path 9. The inducted air atthe end of the ventilation duct 40, in the region of a filter assembly48, is cleaned of contaminations such as microbes and bacteria. Theinflowing air ensures a pressure equalization in the liquid reservoir 30such that the negative pressure existing in the interim is reduced.

FIG. 3 shows a modification of the dispenser of FIG. 1, presently inparticular a modification of the applicator device 12. The modificationlies in that the housing 20 is of a different type and surrounds adetection installation 50 which is designed for detecting air flowing inthrough the ventilation duct 40. The detection installation 50 possessesan acoustic signal emitter 67 in the form of a loudspeaker, amicroprocessor 64, and an energy source in the form of a battery 62.

The detection installation 50 furthermore possesses a sensor assembly 52in the ventilation duct 40, said sensor assembly 52 being provided inparticular on the wall of said ventilation duct 40. This sensor assembly52 comprises two temperature sensors 56 and a heating element 58disposed therebetween. When air now flows through the ventilation duct40 while air is being inducted according to the phase of FIG. 2B, atemperature of said air ahead of the heating element 58 can thus bedetected by the first temperature sensor 56, and the air heated by theheating element 58, in terms of the temperature of said air, can bemeasured downstream of the heating element 58 by the second temperaturesensor 56. The temperature difference is an indicator of whether and howmuch air has flowed through the ventilation duct 40. A high temperaturedifference arises at a small air flow. A small temperature differencearises at a large air flow.

The result of the measurements thereof can be evaluated by themicroprocessor 64. For example, in the event of an excessively small airflow and consequently an earlier excessively low liquid application, themicroprocessor 64 can indicate by way of the loudspeaker 67 that theapplication has not been performed in an orderly manner. Themicroprocessor 64, when delivery times have been stored in the memorythereof, can also indicate by way of the loudspeaker 67 that a plannedapplication has not been performed. The user is thus reminded to make upfor this application.

The disposal of the sensor assembly 52 in the ventilation duct 40results in an application being able to be reliably identified withoutthe sensor assembly to this end having to be in direct contact with theliquid.

The fundamental principle in the design embodiment according to FIGS. 4Aand 4B is similar to that of FIG. 3. As can be seen by means of FIG. 4A,the detection installation 50 presently is however designed as part of adetection module 80 which possesses an annular module housing 82 whichis provided for being pushed onto the housing 20 of the applicatordevice 12. FIG. 4B shows the pushed-on state.

The detection module 80 likewise comprises a battery 62 and amicroprocessor 64. However, an LC display 66, which enables more complexinformation to be relayed to the user than is usually the case with aloudspeaker corresponding to FIG. 3, is additionally provided in thisdesign. However, alternatively to the loudspeaker or additionallythereto, a display may also be provided in the design of FIG. 3 and theintegration of the detection installation 50 in the housing 20 providedthere.

The sensor assembly 52 in the exemplary embodiment of FIGS. 4A and 4B issimilar to that of FIG. 3 and is again based on the presence of twotemperature sensors 56 and one heating element 58. In this case however,the sensor assembly 52 is not an integral component part of theapplicator device 12, in a manner corresponding to FIG. 3, but part ofthe mentioned detection module 80. With reference to FIG. 4A it can beseen that a switch 69, only schematically illustrated, is provided onthe internal side of the annular module housing 82 of the detectionmodule 80. By means of this switch, the detection module can identifywhen the latter is being pushed onto the housing 20 of the applicatordevice 12. This can be utilized for resetting an integrated counter toan initial value, for example. This switch 69 is triggered when thedetection module 80 is assembled.

FIG. 4B shows the assembled state. It can be seen here that a couplingport 45 of the measuring duct 44 of the detection module 80 is connectedin a communicating manner to an introduction opening 41 of the part ofthe ventilation duct 40 that is proximal to the applicator device. Inorder to likewise permit a non-aligned orientation, the housing 20 ofthe applicator device 12 and the module housing 82 of the detectionmodule 80, when in the coupled state, are configured to define anannular space 84. This permits the detection module to be pushed ontothe housing 20 in any arbitrary position.

As has already been mentioned, the sensor assembly 52 is illustrated inthe same manner as in the exemplary embodiment of FIG. 3. The presenceof the LC display 66 however permits the values detected by way of thissensor assembly 52 to be evaluated to an even greater extent andpresented to the user. By detecting the air flow and the duration of theair flow when inducting air through the measuring duct 44 and theventilation duct 40 it can thus be in particular estimated what quantityof liquid has entered the bottle and consequently what quantity ofliquid has previously been applied. Accordingly, the total quantity ofalready applied liquid can be represented on the LC display 66, or elsethe quantity of liquid remaining in the liquid reservoir 30, should theinitial quantity be known to the detection module 80.

The design embodiment of FIGS. 5A and 5B is similar to that of FIGS. 4Aand 4B in terms of the detection installation 50 here also not being anintegral component part of the applicator device 12. However, thedetection installation 50 in this case is provided in the protective cap14. This detection installation also possesses a battery 62, amicroprocessor 64 and an LC display 66. However, the sensor assembly 52which is provided on a measuring duct 44 of the cap 14 is presently of adifferent design, wherein it is fundamentally arbitrary which of theexemplary embodiments is provided with which type of sensor assembly 52.The sensor assembly 52 of FIGS. 5A and 5B possesses a two-part bypassduct 46 which emanates from the measuring duct 44 and in which amembrane 54 is disposed. Depending on the air flow that flows throughthe measuring duct 44, this membrane 54 is deflected to a variableextent, this being able to be detected by means of a piezo sensor, forexample, and to be further processed by the microprocessor 64.

The protective cap 14 moreover likewise possesses a switch 69 whichhowever has a somewhat different technical significance than the switch69 in the case of FIGS. 4A and 4B, as is yet to be explained hereunder.

Because the protective cap is obviously not attached to the applicatordevice 12 during the application of liquid, the applicator device 12possesses a switch valve 42 which in the state of FIG. 5A covers theinduction opening of the ventilation duct 40 and thus does not permitthe induction of air at this point in time. When the dispenser of FIG.5A is thus activated as illustrated in FIG. 2A, an application of liquidis indeed performed, but there is no pressure equalization on account ofinflowing air. Rather, in the case of a multiple application, anever-increasing negative pressure is built up in the liquid reservoir30, said negative pressure not yet able to be equalized at this point oftime.

A detection can only take place once the protective cap 14 is placed onthe applicator device 12, in the manner highlighted by FIG. 5B. First,the switch 69 is triggered, this resulting in an activation of thedetection installation 50. When the cap is depressed as far as theterminal position thereof in FIG. 5B, activation surfaces 15 which areprovided in an encircling manner at the lower end of ribs on theprotective cap 14 can press onto a push-button 43 of the switch valve 42and as a result depress the latter in the manner highlighted by FIG. 5B.As a result thereof, the ventilation duct 40 is opened, however onlyonce the protective cap 14 has been placed to the extent that air cannotflow in along the lower periphery of said protective cap 14 nor throughthe ventilation openings on the end face of the cap. This means that thepressure equalization, which at a high negative pressure is rathershock-like, is performed through the measuring duct 44 of the detectioninstallation 50 which has previously been activated by the switch 69 onthe cap.

The microprocessor 64 of the detection installation 50 can then displaypertinent data on the LC display 66, in particular the overall quantityof liquid applied to date, or else the quantity of liquid stillremaining in the liquid reservoir 30. The shock-like pressureequalization is moreover advantageous for separating potential remnantsof liquid which remain on the filter assembly 48 from the latter.

As soon as the sensor assembly 52 can no longer detect an air flow inthe measuring duct 44, said sensor assembly 52 can change to a powersaving mode or completely deactivate itself until the switch 69 istriggered the next time. As a result of the latter, the protective cap14 can assume the function thereof as a protective cap recording theapplication over a long time, even in the case of only a small battery62.

1. A dispenser for applying liquid, having the following features: a.the dispenser has a housing having an applicator opening for applyingliquid; and b. the dispenser has a liquid reservoir for storing theliquid prior to the application; and c. the dispenser has a ventilationduct by which an ambient atmosphere is connected to the liquid reservoirso as to, after the application of liquid, permit an inflow of air fromthe atmosphere into the liquid reservoir; d. the dispenser has adetection installation for detecting an application procedure; and e.the detection installation is configured for detecting the air flowingin through the ventilation duct.
 2. The dispenser as claimed in claim 1,having the following additional feature: a. the detection installationhas a sensor assembly for detecting the air flowing in through theventilation duct, wherein the sensor assembly is configured fordetecting a differential pressure between two locationally spaced apartreference points of the ventilation duct; and/or the sensor assembly hasat least one deflectable surface portion which is deflectable by the airflowing through the ventilation duct; and/or the sensor assemblycomprises at least two temperature sensors and at least one heatingelement which are disposed in the ventilation duct, wherein the twotemperature sensors are provided upstream and downstream of the heatingelement.
 3. The dispenser as claimed in claim 1, having the followingadditional features: a. the detection installation is configured fordetermining the quantity of liquid previously applied indirectly by wayof the air flowing in through the ventilation duct; and b. the detectioninstallation has a display installation and is configured for informinga user about the determined applied quantity of liquid or, calculatedtherefrom, the quantity of liquid remaining in the liquid reservoir, byway of the display installation.
 4. The dispenser as claimed in claim 1,having the following additional feature: a. the detection installationis configured for identifying application procedures indirectly by wayof the air flowing in through the ventilation duct.
 5. The dispenser asclaimed in claim 1, having at least one of the following furtherfeatures: a. the dispenser is configured as a squeeze-bottle dispenserand possesses a liquid reservoir which for the purpose of applying theliquid is manually compressible from the outside; and/or b. the liquidreservoir has a maximum volume between 5 ml and 500 ml; and/or c. thedispenser is configured as a drop dispenser and in the region of theapplicator opening possesses a drop-forming surface; and/or d. thedispenser is configured as a pharmaceutical dispenser and has a liquidreservoir which is filled with a pharmaceutical liquid.
 6. The dispenseras claimed in claim 1, having the following additional feature: a. thedetection installation is configured in the form of an externaldetection module.
 7. A dispenser for applying liquid, having thefollowing features: a. the dispenser has a housing having an applicatoropening for applying liquid; and b. the dispenser has a liquid reservoirfor storing the liquid prior to the application; and c. the dispenserhas a ventilation duct by which an ambient atmosphere is connected tothe liquid reservoir so as to, after the application of the liquid,permit an inflow of air into the liquid reservoir; d. the dispenser hasa protective cap for covering the applicator opening, which is able tobe placed on the housing and able to be removed from the housing; e. thedispenser in the ventilation duct has a switch valve which can be openedby activating a push-button provided on the external side of thehousing; and f. the housing and the protective cap are mutually adaptedin such a manner that the protective cap acts on the push-button in thestate placed on the housing or when the protective cap is being placedon the latter, thus opening the switch valve.
 8. The dispenser forapplying liquid as claimed in claim 7, having the following furtherfeatures: a. the dispenser has a detection installation for detecting anapplication procedure; and b. the detection installation is configuredfor detecting the air flowing in through the ventilation duct.
 9. Thedispenser for applying liquid as claimed in claim 8, having thefollowing further feature: a. the detection installation is integratedin the protective cap.
 10. The dispenser for applying liquid as claimedin claim 8, having the following further feature: a. the detectioninstallation possesses a switch which is activatable by placing theprotective cap on the housing.
 11. The dispenser for applying liquid asclaimed in claim 8, having the following further feature: a. thedetection installation is configured for determining the air flow in theventilation duct as a reaction to the protective cap being put in place.12. A detection module for a dispenser as claimed in claim 1, having thefollowing features: a. the detection module is configured for beingexternally coupled to the housing of the dispenser, the dispenser havinga ventilation duct having an induction opening disposed on an externalside of the housing; and b. the detection module has a measuring ductand is configured for detecting the air flowing through the measuringduct; and c. the measuring duct has a coupling port which, when thedetection module is coupled to the housing, is coupled so as tocommunicate with the induction opening of the ventilation duct of thedispenser.
 13. The detection module as claimed in claim 12, having thefollowing additional feature: a. the detection module has an annularmodule housing which surrounds a central recess such that said modulehousing can be pushed onto the dispenser housing so as to surround thedispenser housing.
 14. A dispenser set having the following features: a.the set comprises a dispenser having a housing and an applicator openingfor applying liquid, a liquid reservoir for storing the liquid prior tothe application, and a ventilation duct by which an ambient atmosphereis connected to the liquid reservoir so as to, after the application ofliquid, permit an inflow of air into the liquid reservoir; and b. theventilation duct of the dispenser has an induction opening on anexternal side of the housing; c. the set comprises a detection moduleconfigured for being externally coupled to the housing of the dispenser,the ventilation duct of the dispenser having an induction openingdisposed on an external side of the housing; d. the detection module hasa measuring duct and is configured for detecting the air flowing throughthe measuring duct; and e. the measuring duct has a coupling port which,when the detection module is coupled to the housing, is coupled so as tocommunicate with the induction opening of the ventilation duct of thedispense. f. the detection module and the housing of the dispenser aremutually adapted in such a manner that the coupling port of themeasuring duct of the detection module, when the detection module—iscoupled to the housing of the dispenser, is coupled so as to communicatewith the ventilation opening of the ventilation duct of the dispenser.15. The dispenser as claimed in claim 4, wherein the detectioninstallation possesses an internal clock and is configured for comparingplanned utilization times and performed application procedures and, inthe event of outstanding application procedures at planned utilizationtimes, to emit a warning signal by way of a signaling installation. 16.The dispenser as claimed in claim 5, wherein the drop-forming surface isexternally delimited by a tear-off edge.
 17. The dispenser as claimed inclaim 6, wherein the detection module is attached to the housing of thedispenser in a tool-free manner and is releasable from the housing in atool-free manner.
 18. The dispenser as claimed in claim 17, wherein thedetection module possesses a switch activatable by fastening thedetection module to the housing.